Frequently Asked Questions

Question:
Will a fluorescent light fixture provide sufficient light for seedlings?
Answer:

A standard fluorescent shop fixture containing two 40-watt tubes provides sufficient light to grow seedlings indoors.  For best results, place one cool white and one warm white tube in each fixture.  Place the fluorescent lights no more...

Question:
Which trees and shrubs have colorful fruit in winter?
Answer:

The drab winter landscape can be brightened with several trees and shrubs with colorful, persistent fruit.

Trees and shrubs with colorful fruit in winter.

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Common Name
Question:
Which perennials are most likely to be heaved up out of the ground in winter?
Answer:

Repeated freezing and thawing of the soil during the winter months can lift up or heave some perennials out of the soil.  Heaving exposes the plant’s crown and roots to cold, dry air.  Perennials that have been heaved up out of the...

Question:
I recently purchased a primrose at a florist. How do I care for it?
Answer:

Primroses (Primula species) are typically sold at florist shops and greenhouses in late winter or early spring.  Plants produce attractive, 1- to 1½- inch-diameter flowers above a rosette of leaves.  Flowers may be white,...

Question:
What is the proper temperature for houseplants during the winter months?
Answer:

Most houseplants grow well with daytime temperatures of 65 to 75°F and night temperatures of 60 to 65°F.  Temperatures below 50°F or rapid temperature fluctuations may harm some plants.  Keep houseplants away from cold drafts, radiators...

Question:
How should I prune a newly planted tree?
Answer:

Trees utilize sugars and other carbohydrates manufactured by the foliage for plant growth.  Therefore, avoid the temptation to severely prune newly planted trees.  Severe pruning reduces the tree’s ability to manufacture food and...

Question:
What type of germination medium should I use to start seedlings indoors?
Answer:

The germination medium should be lightweight, porous, and free of pathogens.  Excellent seed-starting media are commercially prepared soilless mixes, such as Jiffy Mix.  Use a high quality, well-drained potting mix when transplanting...

Question:
When should dormant oil sprays be applied to apple trees?
Answer:

Dormant oil sprays are highly refined petroleum products that are mixed with water and applied to trees and shrubs to control aphids, spider mites, and scale.  Dormant oils destroy pests by suffocating them.  When applied properly, the...

Question:
Which shrubs have attractive bark in winter?
Answer:

One of the most beautiful sights in winter is the bright red twigs of redosier dogwood (Cornus sericea) set against a backdrop of newly fallen snow. Native to Iowa, the redosier dogwood grows 6 to 10 feet tall. Several colorful varieties...

Question:
When should I start tuberous begonias indoors?
Answer:

Plant tuberous begonia tubers indoors 8 to 10 weeks before the average last spring frost in your area.  (Flowering typically begins 12 to 14 weeks after planting.)  Start tuberous begonias in pots or other suitable containers.  All...

Question:
I received a miniature rose for Valentine's Day. How do I care for it?
Answer:

Light Requirements

Miniature roses need direct sun.  In the home, place the miniature rose in a south or west-facing window.  Rotate plants once or twice a week to promote even growth. 

Watering

Miniature...

Question:
How can I raise the relative humidity indoors for my houseplants?
Answer:

Many houseplants prefer a relative humidity of 40 to 50 percent.  Unfortunately, the humidity level in many homes during the winter months may be only 10 to 20 percent.  Humidifiers are an excellent way to increase the relative humidity...

Question:
When would be a good time to move an evergreen tree with a tree spade?
Answer:

Early spring (before bud break) is the best time to transplant evergreens.  Evergreens can also be transplanted in late summer (late August to mid-September).  Evergreens transplanted after mid-September may not have adequate time to...

Question:
When should I sow my flower and vegetable seeds indoors?
Answer:

The growth rate of the seedlings and the outdoor planting date determine when to sow seeds indoors.  The crop time (number of weeks from sowing to planting outdoors) for several popular flowers and vegetables are as follows: 10 to 12 weeks...

Question:
I have an old apple tree that is starting to decline. I don't know the variety, but would like another tree. How can I propagate it?
Answer:

Apple trees don’t come true from seed.  Grafting is the best way to propagate an apple tree.  Grafted apple trees produce fruit that are identical to their parent. 

Grafting is the joining together of two plant parts (scion...

Question:
How do you force branches of spring-flowering trees and shrubs indoors?
Answer:

Forcing can be done as soon as the buds start to swell.  Forsythia and pussywillow can be forced as early as February.  It's best to wait until March for more difficult-to-force ornamentals, such as crabapples, magnolias, and redbuds....

Question:
Is it possible to grow cannas from seed?
Answer:

Cannas are normally grown from rhizomes.  However, it is possible to grow cannas from seeds.  Canna seeds have hard seedcoats.  Prior to sowing, soak the seeds in water for 24 hours.  Sow the seeds in a commercial germination...

Question:
I recently received a flowering azalea as a gift. How do I care for it?
Answer:

In the home, place the azalea in a brightly lit, cool location.  An ideal site is near a window that receives bright light (but no direct sunlight) and temperatures of 60 to 65°F. 

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Question:
The air in our home is extremely dry in winter. Should I mist the houseplants?
Answer:

Many houseplants prefer a relative humidity of 40 to 50 percent.  Unfortunately, the humidity level in many homes during the winter months may be only 10 to 20 percent. 

Misting houseplants is not an effective way to raise the...

Question:
What is the proper way to prune a large tree branch?
Answer:

To prevent extensive bark damage, use a 3-cut procedure when pruning branches that are greater than 1½ inches in diameter.  Make the first cut 6 to 12 inches from the main branch or trunk.  Cut upward and go about one-third of the way...

Question:
Do I need to purchase a heat mat to successfully germinate seeds indoors?
Answer:

Most seeds germinate best when the medium temperature is consistently 70 to 75 degrees Fahrenheit.  Placing containers in a warm location in the house, such as on top of a radiator or near a heat register, usually works fine.  In cool...

Question:
When is the best time to prune grapevines?
Answer:

The most desirable time to prune grapevines is late winter or early spring.  In Iowa, pruning can begin in late February and should be completed by early April.  Grapevines pruned at this time of year may “bleed” heavily.  However...

Question:
It's only February, but my tulips are coming up. What should I do?
Answer:

Tulips, daffodils, and other spring-flowering bulbs normally begin emerging from the ground in March or early April in Iowa.  However, mild winter weather can encourage premature growth.  The early emergence of spring-flowering bulb...

Question:
What is the proper care for a moth orchid?
Answer:

Lighting Requirements

Moth orchids (Phalaenopsis spp.) are one of the easiest orchids to grow indoors.  Moth orchids grow best in bright, indirect light.  Direct sun may actually harm the foliage.  Ideal sites are...

Question:
How often should I fertilize houseplants?
Answer:

Spring and summer and the best times to fertilize houseplants.  Fertilizers are available in liquid, crystalline, granular, spike, and tablet forms.   Utilize fertilizers specifically formulated for houseplants or use general...

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